Mid-term shoulder functional and quality of life outcomes after shoulder replacement in obese patients

BACKGROUND: Shoulder pain and loss of function are directly associated with obesity. QUESTIONS/PURPOSES: We hypothesized that significant interactions would exist between total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA) and obesity status on functional and quality of life (QOL) outcomes over the long term. Clinical and QOL outcomes (American Shoulder and Elbow Surgeons Evaluation form, Shoulder Pain and Disability Index, University of California at Los Angeles Shoulder Rating scale, Medical Outcomes Short Form 12 (SF-12), range of motion (ROM), and strength) were longitudinally compared in patients with low and high body mass index (BMI) after a TSA or a RSA. Prospectively collected data of patients with a TSA or RSA were reviewed (N = 310). Preoperative, 2-year, and final follow-up visits were included (range 3–17 years; mean 5.0 ± 2.5 years). Patient data were stratified for analysis using BMI. RESULTS: Morbidly obese patients had worse preoperative functional scores and QOL compared to the other groups. There were no significant interactions of BMI group by surgery type for any of the outcome variables except for active external rotation ROM. Morbidly obese patients attained lower SF-12 scores compared to the remaining groups at each time point. CONCLUSIONS: Both TSA and RSA can be expected to impart positive functional outcomes in patients irrespective of BMI. Morbidly obese patients do not attain the same gains in Medical Outcomes SF-12 scores as the non-morbidly obese patients. The lower improvements in active external ROM may be due to morphological limitations of excessive adiposity. LEVEL OF EVIDENCE: This is a level II study.